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^J I «"
~j/ v REPORT NO. 282
~~fyi^t>h
COO-1U69-0102
A TRICOLOR CARTOGRAPH
by
William J. Kubitz
SEPTEMBER, I968
DEPARTMENT OF COMPUTER SCIENCE • UNIVERSITY OF ILLINOIS • URBANA, ILLINOIS
Report Wo. 282
A TRICOLOR CARTOGRAPH *
by
William J. Kubitz
September, I968
Department of Computer Science
University of Illinois
Urbana, Illinois 6l801
* Submitted in partial fulfillment for the Doctor of Philosophy Degree
in Electrical Engineering, at the University of Illinois, September, 1968,
A TRICOLOR CARTOGRAPH
William John Kubitz, Ph.D.
Department of Electrical Engineering
University of Illinois, 1968
A system for coloring the interior of closed boundaries on a
television-like display is described. The coloring is accomplished in
a semi-automatic manner by using a light pen to indicate any point on
the interior of the boundary. Given any interior point, the system will
color all or most of the entire interior area automatically. The colors
are chosen by the operator from red, blue, green and their combinations.
Local writing and erasing on the color display is also allowed. The
system is a self-contained display console and does not rely on the
back-up of a general purpose digital computer. Boundaries may be input
directly be means of the light pen or by a television camera or a flying
spot scanner. A discussion of the problems associated with the automatic
coloring of closed bounded areas is given.
Ill
ACKNOWLEDGMENT
The author wishes to express his appreciation to Professor
W. J. Poppelbaum for suggesting the overall system as well as his
advice and guidance, to the members of the Hardware Research Group for
their helpful discussions, to Carla Donaldson for the typing and to the
Drafting Department of the Department of Computer Science for making
the drawings .
IV
TABLE OF CONTENTS
Page
1. Introduction 1
2. The Problem of Coloring 6
2.1 Theoretical Requirements 6
2.2 Practical Requirements 8
3- Realizable Solutions and Restrictions 9
3.1 The Memory 9
3.2 The Processor 15
3.3 The Display 23
4. Description of System 24
4.1 Brief Review of Television Concepts 24
k.2 Physical Description 26
k . 3 The Pen ■ 28
k.k The Display 30
4.5 The Memory 31
k.6 The Processor 33
k.6.1 The Total Erase Operation 33
4.6.2 The Pen Modes 33
4.6.3 The Coloring Operation 34
5. Discussion of Results, Suggested Improvements and Conclusions 48
APPENDIX 54
BIBLIOGRAPHY 108
VITA 109
V
LIST OF FIGURES
Figure Page
1. The Tricolor Cartograph 3
2. An Automatically Colored Figure 5
3. Open Boundaries and Multiply Connected Regions 7
4. Scanning Methods 17
5. Boundary and Pen Tracing 19
6. Problem Boundaries 21
7. Tricolor Cartograph 27
8. Tricolor Cartograph Block Diagram 29
9. Top and Bottom Point Location 36
10. Left and Right Point Location 37
11. Coloring the Entire Figure 3^
12. Timing Diagram for Coloring Operation 40
13- Errors in Finding the Right and Left Points 44
14. Simplified Diagram of Coloring Logic 47
15. The Bleeding Problem 49
16. Leakage Through a Gap 51
17. Control and Video Logic 56
18. Coloring Logic 60
19. Pen Preamplifier 1469-121 71
20. Counter Buffer 1469-133 72
21. Horizontal Counter 1469-134 73
22. Dual 9-Bit Register 1469-135 74
23. 8-Bit Register and Coincidence 1469-136 75
24. R-S Flip Flop 1469-137 76
VI
Figure Page
25- Vertical Counter 1469-138 ; 77
26. 9-Bit Register and Coincidence 1469-139 78
27. Switch Matrix 1469-140 79
28. 2-Bit Coincidence and R-S Flip Flop l469-l4l 80
29. Total Erase Control 1469-145 8l
30. Level Shifter 1469-156 82
31. One Shot Buffer 1469-159 83
32. General 2- Input Nand l469-l6l 84
33- General 3- Input Nand 1469-162 85
34. Switch Filter 1469-173 86
35. Logic to Video Converter 1469-175 87
36. Indicator 1469-176 88
37. Video to Logic Converter 1469-177A 89
38. +1 Volt Power Supply /Mode Switch 1469-178 90
39- Pen Shaper and Gate 1469-179 91
40. 3- Input Video Adder 1469-180 92
41. General 4- Input Nand l469-l8l-20 93
42. General J-K Flip Flop l469-l8l-70 9^
43. Voltage Controlled Oscillator 1469-184 95
44. Main Junction Box 96
45. Display Junction Box 97
46. Circuit Breaker Panel 98
47. Modular Power Supplies 99
48. Switch Panel 100
49. Cable Details 101
-1-
1. INTRODUCTION
In recent years great interest has developed in the area of
graphical displays and graphical display systems. This interest has
resulted primarily from the increasing use of large digital computers
for information processing. Because these computers are capable of gen-
erating large amounts of information at high rates, it has become neces-
sary to search for means of information display which can more nearly
match their speed. In addition, there is a continual search for some
better means of communication between man and his machines and it is
thought that some improvement can be obtained by the use of visual display
techniques. A cathode ray tube display is probably the most common type
in use today. However, there are many other types in current use ranging
from small arrays of light bulbs to large screen types involving pro-
jection techniques. Although most displays are black and white in nature,
a few do utilize color. Often, the additional complexity of color is
not considered worthwhile for a given application. However, color will
probably become more popular in the future when some of the technical
problems associated with its use are overcome.
For displays associated with computers, until recently the
common practice was to operate the display directly from the computer.
This technique becomes troublesome when the amount of information on the
display becomes large because considerable computing time and memory
space are utilized just to regenerate the display. With the advent of
the time-sharing concept for efficiently and conveniently utilizing
large computers, some consider it only natural that each remote station
have a display. Thus, the recent trend has been toward having a local
buffer store associated with the display unit. Even more recently, there
appears to be a return to a raster-scan type display in c
character generation type scan currently in use. The reasons for these
changes are partly technological and partly practical. Practically,
they are a result of the desire to present more data and posess more
versitility in the display format. Technologically, they are the result
of the development of high density storage at a reasonable cost and
recognition of the already advanced state of standard television techniques,
Concurrent "with and in association with these recent developments
in computer displays there has been an upsurge of interest in specilaized
digital systems which although lacking the versitility of the general
purpose computer, perform some specialized operations much more simply
and more efficiently than the general purpose machine. Quite probably
the future will bring many specialized "computers", some of which will
have displays associated with them and most of which will be connected
to a large central machine which can be called upon in the few instances
when its use is required.
The Tricolor Cartograph (Figure l) is a specialized display
system which is restricted in its operations. It is self-contained and
is not associated with a general purpose digital computer. It consists
of a color display unit with a light pen and associated control buttons.
The operator sits in front of the display and uses the light pen and
buttons to perform certain operations. The operations which can be
performed are: writing on the display with the pen in choice of color,
erasing from the display with the pen in choice of color, drawing or
erasing closed outlines on the display with the pen (in white), totally
erasing any color or all outlines from the display and designating the
interior of any closed outline which is to be colored-in with a previously
-3-
Figure 1. The Tricolor Cartograph
-U-
selected color. The color information which is displayed is stored
a video signal on a magnetic disc. Figure 2 shows an example of a figure
which has been automatically colored on the Tricolor Cartograph.
Thus, the Tricolor Cartograph is a color graphical display
system with self contained storage which can perform a few specialized
operations independently of a central computer system. In particular,
it can relieve a central processor from the duties of the storage of
graphical information and the coloring of large irregular areas.
There are many possible uses for a system which can perform
automatic coloring. Some possible areas of use are air traffic control,
radar, map layout, printed circuit mat layout, pictorial computer simu-
lation and sketching. It may be possible some day for an artist to
"paint" a picture on such a display and then obtain a color reproduction
from a color facsimile machine.
■5-
Figure 2. An Automatically Colored Figure
-f -
2. THE PROBLEM OF COLOR]
2.1 Theoretical Requirements
In order to color the interior of a figure or a part of a
figure, certain information about the figure must be known; namely, the
color and which area is to be colored.
The color is a matter of choice for the operator. Color is
characterized by two quantities, the hue and the saturation. Hue pertai
to the actual color and saturation to the shading or grayness of the hue.
Of course, both of these are arbitrary choices and vary over a fairly
large continuous range (blue to red, white to black). In a practical
system it is usually necessary to place limitations on this range.
The area to be colored is defined by a boundary. If the
boundary is not closed or if it bounds a multiply connected region,
additional information is required in order to define what is to be
colored. Thus, the following rules are established for the purpose of
discussion: If the boundary is not closed, it is assumed that both the
inside and outside are to be colored. The outside consists of all the
area within the next largest closed boundary in the case of multiple
boundaries or the whole plane if there are none. In the case of multiple
connected regions, the coloring takes place only in the region designated
and does not cross into an adjacent region, unless of course there is a
gap in the boundary. To put it simply, the coloring covers the largest
area with a closed boundary and does not cross closed boundaries. These
cases are illustrated in Figure 3- In theory, the solution to this
problem is simple: Given an initial point known to be inside the boundary,
color all adjacent points not on or beyond a boundary. Although this
-7-
A. Open Boundary
B. Multiply Connected
Figure 3. Open Boundaries and Multiply Connected Regions
method can be realized, it is not simple or practical for large nu'
of points. Because of this, other methods were explored. These are
discussed in Section 3«
Thus, from a theoretical point of view the following information
must be known: the closed boundary, the hue, the saturation and sc
point which determines in some way which side of the boundary the coloring
is to begin on (an initial point).
2.2 Practical Requirements
At this point in the discussion four requirements of the
coloring system have been stated. The color (hue and saturation) must
be known, the closed boundary must be known and a defining point must be
given. In order to accomplish reasonable automatic coloring in an
electronic system, some other requirements must be added. First, the
actual coloring must be accomplished in a reasonable time (0.1 - 0.2
seconds for example). Second, it must be accomplished at a reasonable
cost. Third, the coloring operation should be as automatic as possible,
requiring a minimum number of manipulations by the operator. Fourth,
the resolution and registration of the colored area and the outline should
be good.
Thus, there are four theoretical requirements and four practical
requirements which must be satisfied in order to accomplish reasonable
automatic coloring.
-9-
3. REALIZABLE SOLUTIONS AND RESTRICTIONS
In addition to the theoretical and practical requirements of
the coloring operation, in a realizable system it may be necessary to
impose certain restrictions depending on the choice of memory, control
and display units to be used. In the following sections these restric-
tions are discussed with regard to particular choices of the memory,
display and control.
3-1 The Memory
In order to attain what is commonly called a "flicker free"
display it is necessary that the memory be continuously read out and
displayed. This requirement can frequently be relaxed to some extent by
utilizing a display tube with long persistence. Such is not the case
for color since there is no color tube with long persistence available.
A necessary requirement of the system is the capability of
writing into the memory with the light pen in order to write and draw
boundaries on the display. Therefore, the memory must possess a local
writing capability. It is also desirable that local erasure be available
so that one may make small corrections to what has been drawn or written
on the display. Also, it is necessary to possess the capability of
totally erasing all colors and all outlines. In addition, the storage
should be indefinite so that the display may be viewed for long periods
of time without noti cable deterioration. Finally, the memory must
possess enough capacity to allow storage of the required information.
For a resolution of 500 lines vertically and horizontally,
250,000 elements must be stored. Since there are three primary colors
the number of required elements increases to 750,000. The fact that
-10-
750,000 are re {uired rather than 500, 000 results from the fact that tl
three primaries yield eight possible signals: red, blue, grei
yellow, magenta, white and black. Thus, although two bits is sufficient
to encode the individual colors red, blue and green, three bits are
re iuired if all combinations are allowed. Storage of the outlines
(boundaries) in addition to the colors results in a total of 10 stored
elements. If shades of gray are desired and must be stored digitally
then two bits are required for each color for four shades of gray. This
requires 1.5 x 10 bits for the colors, 0.25 x 10 more for the outlines
(assuming no shades of gray) for a total of 1.75 x 10 bits. If the
shades of gray can be stored as an analog signal then the capacity required
6
is 10 bits (250K for each color and the outline). Of course, at any
given time the actual capacity being used would normally be less than any
of these figures. However, since there is no restriction on the size or
shape of the objects written on the display, the capability for storing
these capacities must be present. As an alternative scheme to storing
the individual picture elements one could, for example, consider storing
a point by means of storing the address of the point on the display in-
stead of the point itself. For a 500 x 500 display this requires the
storing of 9 bits for the X address, 9 bits for the Y address and 3 bits
for the color or for each point, a total of 21 bits. Thus, for the same
memory capacity (750K) only 1/7 (l^$) as many points can be stored. This
is clearly inadequate for large colored areas which can easily cover 80%
of the screen. In addition, it would be impossible to maintain a reasonable
regeneration rate if each point had to be decoded and converted to an
analog signal in order to generate the appropriate deflection for dis-
playing that element. Finally, it should be mentioned that 500 elements
-11-
horizontally results in a capability of storing 250 line pairs (alter-
nating "black and white for example) . Thus the actual number of lines
resolution (white on a black background or vice versa) for 500 elements
is 250. Also, in order to read out 500 elements in a standard television
format, a reading rate of 10 bits /sec is required. (See Section k for
a discussion of the standard television format.)
Various types of storage media are available today which can
be considered for possible use: magnetic tape, magnetic cores, magnetic
drum, magnetic disc, direct view storage tubes, electrical in - electrical
out storage tubes and scan conversion tubes.
Magnetic tape is not suitable for graphical storage because of
insufficient reading rate and the unavailability of local erase capability.
Although commercial color recorders are available (which do not have local
erase capability) , they usually utilize NTSC encoding or some similar
scheme. Under these conditions the color information is of low resolution.
The addition of local erasure to this type of system is difficult since
the information stored on the tape is encoded. Finally, the cost of these
machines is quite high.
A core memory could be used if the required capacity could be
achieved at a reasonable cost. In order to read out of such a device,
500 bits are required in 50 usee or one 6U bit word every 6 usee. This
would be no problem for some memories available. However, the cost of
such a device is high enough to make it impractical. Added to the cost
of the core memory, of course, is the additional circuitry required to
convert from a parallel readout to the serial readout as required by the
display.
A magnetic drum could be used. In order to achieve the
required reading rate, however, a large drum would be required. Again
the cost of such a device is high. Nonetheless, some current dispj
systems are successfully making use of drums.
It is also possible to use a direct view electrostatic st .
tube. The direct view tube has electrical signal input and a visual
display for output by means of a viewing screen. This type tube suffers
from the disadvantage that in order to achieve electrical readout, it is
usually necessary to view the tube with a photo sensitive pick-up device.
This type of memory cell was investigated in the ARTRIX project at the
University of Illinois Digital Computer Laboratory. In addition to the
difficulties associated with obtaining readout, these tubes have low
resolution for long persistence and short persistences for high resolution.
Recently, Tektronix has developed a tube with about 15 minutes storage
time and a resolution of 800 (TV) lines vertically and 600 (TV) lines
horizontally. The tube is large, however, so that the density is only
about 95 (TV) lines/inch. The writing speed of this tube is also low.-
Even with these disadvantages, this tube is an improvement over what has
been available in the direct view storage tube field. Lack of local
erasure capability is another disadvantage of these tubes.
Another type of storage tube has electrical input and electrical
output and is frequently used for scan conversion. The problems associ-
ated with these tubes are short storage time under continuous readout
operation and beam registration problems when switching tube potentials
in order to go from a writing mode of operation to an erasing mode of
operation. These tubes do have adequate writing speed and excellent
resolution, however.
A storage tube with inverse properties would be very useful for
coloring. In such a tube the storage surface would be conductive until
it had been written on by an electron beam or incoming light. In an area
-13-
where it had been written it would then become insulating. If the in-
sulated area is the boundary of the region to be colored, then a small
amount of charge deposited inside the region initially will spread
uniformly over the interior of the boundary. Upon scanning the tube,
an electrical signal will be produced which represents the area which was
to be colored. The possibility of such a device is being explored at
the University of Illinois Digital Computer Laboratory. The major draw-
back to this scheme seems to be finding a material which becomes non-
conducting rather than conducting under some form of exitation. It may
be possible to use the usual photoconductive effect in conjunction with
a black trace cathode ray tube instead, however.
Finally, the magnetic disc is a possible storage media. Until
recently, the disc did not possess sufficient storage or a high enough
reading rate. However, current announced devices are approaching the
necessary rate and capacity for the storage of pictorial information.
These new discs are manufactured by Data Disc, Inc. of Palo Alto, Cali-
fornia. Data Disc uses a proprietary method of producing their discs
along with in- contact heads to achieve digital storage of 10 bits /track
and bit rates of 3 x 10 bits/sec for a 12" disc. It is possible to get
6k tracks on a disc for a storage capacity of 6k x 10 bits. Specifi-
cations claim video recording frequencies up to U.2MHz and recording has
been done up to 5MHz. Under development are higher capacity disc systems.
• A comparison of possible storage media is shown in Table 1.
As indicated by the table, the disc possesses local write and erase, total
erase, continuous read and long-term storage capability. In addition,
it can store k or 5 shades of gray. For these reasons the disc was
chosen as the memory element for the Tricolor Cartograph. Because the
capacity for the disc chosen is 10 bits with a bit rate of 3 x 10 , the
COMPARISON OF MEMORIES FOR TRICOLOR CARTOGRAPH
-Ik-
^\ STORAGE
\MEDIA
REQUIREMENT \.
<
EH
w
o
o
o
CO
M
n
DIRECT VIEW
STORAGE TUBE
SCAN
CONVERTER
CONTINUOUS READ
X
X
X
X
X
X?
LOCAL WRITE
X
X
X
X
x
X
LOCAL ERASE
?
X
X
X
-
9
TOATL ERASE
X
X
X
X
X
X
INDEFINITE STORAGE
X
X
X
X
X
-
CAPACITY
AND
READ RATE
-
X?
X?
X?
-
X
COST
H
H
H
M
M
H
GRAY LEVEL STORAGE
X
X?
X?
X
-
X
H = HIGH
M - MODERATE
TABLE 1.
-15-
resolution of the system cannot be 500 elements. A discussion of the
characteristics of the actual system will be found in Section k.
It should be pointed out that storage units with insufficient
reading rates can be used by multiplexing several channels and using an
intermediate fast storage media. Such methods were considered to be too
complex and were thus not considered. What was desired was a memory
which could be read and displayed without complex interfacing.
3-2 The Processor
The major problem associated with the processor is that of
detecting the boundaries of a figure such that their location is determined
in some meaningful way. If one assumes that the format of the pictorial
data can take any form, then several scanning methods seem to offer promise
as a means of boundary detection. These are: the spiral scan, the radial
scan, the bounce scan and the lineal scan with and without pen or boundary
tracing. In addition, a boundary enumeration scheme can be considered
with the lineal scan.
For the spiral scan, the scanning of the boundary is done
starting at a point indicated by the light pen (and known to be inside
the boundary of interest) and spiraling out from this point until it
intersects a boundary. During the time it is spiraling, coloring takes
place. One disadvantage of this method is that the only figure that
could be colored in one operation is a circle. A scheme could be imple-
mented which would only sense the boundary (allowing the scan to continue)
and stop the coloring, allowing it to commence again after again sensing
a boundary. With this scheme, coloring would result after each even
number of intersections with a boundary. The possible occurrence of
adjacent boundaries and cusps, however, eliminates the usefulness of this
SO.hPTIlP .
-16-
Use of a radial scan is also possible and would probably yield
somewhat better results than the spiral scan for most figures. For the
radial scan, scanning again begins at a point determined by the light ;
and radiates from it while slowly moving about it in a circular manner.
However, it, too, could not cover all of a figure in one operation and in
addition, it suffers from non-uniformity since adjacent scan lines diverge
with increasing distance from their starting point.
The lineal scan consists of scanning the figure with parallel
scans. These could be horizontal, vertical or at some oblique angle.
With this method, given the initial point, it would be necessary to scan
both ahead of and behind this point (unless it was on the boundary). Again.
it would not be possible to cover all of some figures in one operation
utilizing a single scanning direction. If, however, two orthogonal
directions can be used it is possible to color the entire figure. In
this case, however, it is difficult to determine when to cease scanning in
one direction and commence scanning in the other. The radial, spiral, and
lineal methods are illustrated in Figure k.
It is interesting to note in passing that when a human colors
a bounded area with a pencil, all of the above methods are put in use.
These three scanning methods all require some means of sensing
when the boundary has been reached. This means that when the scan reaches
a boundary, a signal must be produced to signify this fact. If such a
signal could be generated, it would be possible to confine the scanning
to the interior of the boundary. Under these conditions the bounce scan
could be used.
The bounce scan consists of scanning in a given direction until
a boundary is encountered at which time the scan is reversed and directed
away from the boundary and continues until the entire interior has been
-17-
A. Spiral
B. Radia
C. Lineal
Figure h. Scanning Methods
-1/
covered. The disadvantages of this method are difficulties in imple-
mentation of such a scanning system and the problem associated with sensing
when the coloring operation is complete. In order to sense when the oper-
ation is complete, it is necessary that some control be exercised over
the directions of the various bounces of the scan. In other words, some
systematic method of bouncing would be required.
If one is willing to impose more restrictions on the operator,
other scanning methods can be used. Thus, if the operator is required to
move the pen from the upper extremity of the figure to the lower extremity
of the figure (remaining inside the boundary) and a lineal scan is used,
coloring can be done line by line as the pen is moved across the figure.
If a television like scan is used, it is a simple matter to color all
lines starting at the pen and stopping at the next boundary. Coloring
between the boundary prior to the pen and the pen itself is not simple
since the boundary has already been passed when the location of the pen
is sensed. This area would have to be colored on a succeeding pass, which
for a television type scan is too much later to be practical.
This latter difficulty can be circumvented by requiring the
operator to pass the pen either along the boundary or just ahead of it
(with respect to the scan). Under these circumstances, the coloring can
be done between the next two boundary points. Of course, this method
would still not completely color some figures. In addition, the coloring
would most certainly be erroneous if the operator happened to go above
the upper extremity of the figures or below the lower extremity since in
that case the next two boundaries (if they exist) would not be part of the
one which was being used. These three methods of boundary and pen tracing
are shown in Figure 5-
■19-
A. Bounce Scan
B. Interior Pen Tracing
C. Exterior Pen Tracing
Figure 5. Boundary and Pen Tracing
-20-
No matter what scanning methoc. is used there are certain
boundary configurations which can cause problems. The figurations
consist of the cases in which the boundary either becomes tangent to the
scan or divides into two or more boundaries. Some cases for which this
occurs are the cusp, the lobe and the branch as shown in Figure 6. The
cusp and lobe could cause difficulties insofaras they appear as only one
point when the scan is tangent to their tip. This same problem exists
for a boundary which is parallel to the scan. The existence of these
boundary configurations rules out coloring schemes which rely on the
enumeration of boundary points since when these configurations occur they
appear as one, two, three or even more points.
In view of the foregoing discussion, it is clear that the basic
problem associated with the scanning of the figure is determining when
the scan is inside and when it is outside the boundary of interest. In
addition, it cannot be just any boundary but the boundary. Information
on the boundary is available regularly in the process of generating the
display. However, since the disc has been shown to be the only storage
media which is both suitable and available, its use fixes the format of
the data. This format is serial so that information about the boundary
is available only periodically. Unless the boundary information is re-
written in another form, it will be necessary to synchronize the scanning
of the boundary with the periodically appearing boundary information. Of
course, by utilizing a scan converter the disc output may be transformed
into any other type of format. This is also accomplished if the serial
disc information is scanned in a non-lineal manner by sampling the disc
output appropriately. This results in a very low effective scanning rate,
however. By utilizing a scan converter the spiral, radial or lineal
scanning method may be employed. The cost of a scan converter is such as
-21-
A. Cusp
B. Lobe
C. Branch
Figure 6. Problem Boundaries
-22-
to rule out its use in a project the size of the Tricolor Cartograph.
Besides cost there are operational problems such as : the time required
to read and write between the scan converter and the disc, the difficulty
of erasing locally with good registration, the problems associated with
attempting to write (in order to do the coloring) and read (in order to
sense the boundaries) simultaneously and the fact that it is difficult to
prevent the transfer of the outline back into the color memory after the
coloring operation is complete.
Clearly, it would be desirable if the disc output could be
used directly. As a result, a lineal scan which runs synchronously with
the disc is used in the Tricolor Cartograph. This means that the boundary
information from the disc occurs, in time, when the scan reaches the
boundary. In order to store positional information in the system, two
counters are used. The horizontal counter digitizes each horizontal
scanning line into 9 bits. The vertical counter counts the number of
scanning lines. Thus, the horizontal count is an indication of position
on a given scanning line and the vertical count determines which scanning
line. These two counters allow the digital storage of coordinates in the
form of a 9 bit horizontal and a 9 bit vertical binary representation.
During the coloring operation, the required initial point is determined
by the placement of the light pen when the operator indicates some point
within the interior of the chosen boundary. The coordinates of this pen
location are stored at this time and used as a reference point during sub-
sequent operations. While coloring, there are two boundary points of
interest on each horizontal scanning line. These are defined to be the
last boundary point preceding the horizontal pen position and the first
boundary point following the horizontal pen position. The horizontal pen
position referred to is that position which was stored initially when the
-23-
operator designated an interior point. In order to color all of some
figures with this scheme, more than one pen placement will be required.
Since the boundary point preceeding the pen position is not sensed until
after the pen position has been passed, it is then too late to color on
that scan. In order to color the proper line, a wait of an entire frame
would be required. To avoid this, the coloring is delayed just one line.
This means that there will be a misregistration of two lines for the coloring
(the system is interlaced). Since most figures have boundaries which are
slowly varying, this misregistration should not be noticable. A complete
description of the method used is contained in Sections k and 5«
3.3 The Display
Although various methods of displaying color information are in
use currently, only some type of color cathode ray tube is both suitable
for a small console and available at a reasonable cost. Of the color
tubes which have been proposed only the familiar tricolor tube is in wide-
spread usage. Thus, the display unit of the Tricolor Cartograph utilizes
a three color television monitor having a tricolor tube as its display
element. Since these monitors are designed for standard 525 line television
they are directly compatible with the disc memory which is also designed
to operate at standard television rates.
k. DESCRIPTION OF S/STEM
Before embarking on a description of the operation of the Tri-
color Cartograph, a brief review of standard television concepts will be
given.
4.1 A Brief Review of Television Concepts and Nomenclature
Standard television consists of a 525 line scanning format.
When facing a monitor, the lines are scanned from left to right hori-
zontally and from top to bottom vertically. Horizontal scanning is at a
rate of 15,750 lines per second. At this rate, the entire 525 lines is
scanned in 1/30 sec. This is called one frame. Each frame is divided
into two interlaced fields each requiring 1/60 second. The interlacing
is accomplished by starting the vertical retrace of the scanning beam at
an appropriate time (either at the end of horizontal scan or halfway
through it). This interlacing then places the lines of one field halfway
between those of the others.
The two fields are designated even and odd. On the basis of
the above rates, the duration of one line is about 63-5 usee, one frame
33-3 msec, and one field 16.7 msec. It is important to note that neither
the entire 525 lines nor the entirety of any one line is usable for
pictorial information. This results from the fact that time is required
for retrace of the scanning beams. Thus, between 20 and 30 lines are
lost (assume 25) leaving about 500 lines and about 16% of each line is
lost (~10 (i sec.) giving a useable line of about 53 u-sec. duration.
The scanned area is k/3 as wide as it is high. This is called
the aspect ratio. The bandwidth required for a given resolution can
easily be determined. The relationship in the horizontal case is:
-25-
BW = Vt
2K..T.
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where R = number of half cycles per line [R^/2 = # of cycles /line]
N = number of lines per frame
fC = % of line actually used (~Qh%)
T = period of frame (1/30 sec.)
The 1/2 results from the fact that the television industry
counts each cycle as two lines resolution, not one. Thus the resolution
given by R^ is twice the actual resolution. The above gives R^ = 107 lines
per MHz bandwidth.
The vertical resolution is given by:
*v = W.
"where N = actual number of scanning lines (~500)
a
K^ bs the Kel factor (-.7)
K. = 1 if a full interlace is used and 0.75 if a random interlace
1 '
is used.
The Kel factor is a statistical correction which takes into
account the fact that it is not possible to transmit any information
corresponding to the part of the picture which falls between the scanning
lines. They are not "seen" by the camera. Recently, some experimentation
was done in which this factor was "effectively" increased by purposely
causing the raster to move up and down over a period of frames. [of course
for any one frame the factor is still the same.] In this way information
missed in one scan can sometimes be detected during the next. R^ is
about 350 for standard television. It is interesting to note that for
commerical black and white television R^ = 350 and R^ = 350 (the bandwidth
-26-
is 3-3-5MHz). For color television the color information bandwidth is
0.5MHz giving a resolution of about h-0 lines for the color information.
In a television system the required timing pulses are usually
obtained from a crystal oscillator. The basic pulses used to control a
television system are derived from this oscillator and are known as
horizontal and vertical drive (HD and VD), horizontal and vertical syn-
chronization (HS and VS) and horizontal and vertical blanking (HB and
VB) . The drive pulses are used to initiate the horizontal and vertical
scans in the camera or camera systems. They are the basic timing pulses
used in all video processing. The synchronization pulses and blanking
pulses are added to the outgoing video The synchronization pulses are
used to synchronize a receiver and the blanking pulses are used to blank
out its scanning beam during retrace.
The vertical drive pulse is about 0-7 msec, in duration and the
horizontal drive pulse about 6.35 (i sec. The sync and blanking pulses
are wider. The drive pulses are the basic timing pulses used in the
Tricolor Cartograph.
In order to handle color information in a television system,
either three separate video signals (red, blue and green) must be processed
or the three signals must be encoded and processed as a unit. In the
Tricolor Cartograph, three separate channels are used.
h. 2 Physical Description
The Tricolor Cartograph is shown in Figure 7- It consists of
a display console and a control console. The display console contains
the light pen, the control switches and the color display. The control
console contains the power supplies, the processor and the memory. The
color display is a Model CYM 21 Color Television Monitor manufactured by
-27-
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Figure 7. Tricolor Cartograph
-2f
Conrac Division of Giannini Controls Corporation of Glendora, California.
The memory is a Model ^-04 Video Memory manufactured by Colorado Video,
Inc., Boulder, Colorado. The entire system utilizes a standard 525 line
television format, as previously described.
Figure 8 shows a block diagram of the system. Power for the
entire system is obtained through the circuit breaker panel. D.C. power
is supplied by the two modular power supply units which produced -5, +10,
+25 volts. The power is distributed by the Main Junction Box. Control
signals pass through the Display Junction Box to the Main Junction Box
and on to the Control (Processor). Video signals for the monitor eminate
from the Control. All signals to and from the video memory originate or
terminate at the Control. The Light Pen signal passes through the Dis-
play Junction Box and on to the Control.
k.3 The Light Pen
The Light Pen performs two functions. First, it produces a •
signal designated Enable which performs logical functions in 'the Control.
These functions will be described later. Second, it produces an output
pulse in response to light input from the phosphor emission of the Display.
The light produced by the phosphor is detected by a photodiode.
The signal thus produced is amplified by a two stage high pass preamplifier
in the Light Pen. The signal then passes to a thresholding amplifier.
This is a two stage high pass amplifier whose input threshold can be con-
trolled so as to produce some noise immunity. This is necessary because
of the extreme sensitivity of the light pen circuitry in conjunction with
the fact that the television monitor radiates a prominent signal at
15,750 Hz from its flyback circuitry. There is sufficient coupling of
this signal to the pen to cause spurious pulses.
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Figure 8. Tricolor Cartograph Block Diagram
Since the pen is activated by the detection of light from the
raster, it is necessary to display a raster at all times so that the pen
will operate. There is sufficient gain in the system to allow the back-
ground level to be quite low. However, this level must be high enough to
provide an adequate signal to noise ratio for proper operation of the
pen circuits.
After this thresholding and amplification (in the Display Junction
Box) the pen pulse passes to a pen pulse shaping circuit at the Processor.
Here the pen pulse is shaped into a one volt pulse 120 nsec. in width.
This pulse then passes to three 3-input video adders so as to be displayed
as a marker on the display. It also passes to the video to logic con-
verter where it is converted to logic levels and subsequently used in all
pen operations in the Processor.
h.k The Display
The Display is a red, blue, green color monitor utilizing a 21
inch tricolor tube. These tubes use three phosphor grouped in triads
across the face of the tube. The three phosphors are a red emitting, a
green emitting and a blue emitting. The time required for these phos-
phors to decay to 10$ of their initial value is 22 msec, for blue, 60
msec, for green and 1 msec, for red. The relative emitted energy is
highest in the red but the red emission is in very narrow spectral bands
whereas the green, and blue energy is distributed more uniformly. This
results in the total integrated energy being largest in the green followed
by the blue and the red. This results in a very low sensitivity of the
Light Pen to the red phosphor. The pen is most sensitive to green. This
is so even though the intrinsic sensitivity of the photo-diode is much
higher in the red than in the green or blue.
-31-
The triads of phosphor are spaced at intervals of 0.029 inches.
With screen dimensions of 16 x 19 l/*+ the possible resolution is about
550 dots vertically and 650 dots horizontally. The electrical resolution
is 7MHz or 750 lines (i.e. 375 cycles).
One property of the shadow mask tube is that of very low bright-
ness. This results from the fact that the faceplate transmission is only
39% and more important, the shadow mask transmission is only 15%- Because
of this, a fairly low room illumination is needed when viewing the Tri-
color Cartograph.
Four signals drive the color monitor: red, green and blue
video and sync. The sync signal is generated at the disc memory. The
three video signals all originate at the Processor.
4.5 The Memory
The Memory utilizes a magnetic disc 12 inches in diameter driven
by a hysteresis -synchromous motor at 1800 rpm. There are 5 channels: h
video and one sync. The sync track is used to generate horizontal and
vertical drive, horizontal and vertical sync, and blanking. The four video
tracks are used for red video, blue video, green video and outline video.
The outline track contains all the boundary information for the figures.
Each of these k video tracks has two inputs and one output. The inputs
are write and erase and the output is read. There is one additional in-
put to the Memory: chop. The chop input controls an internal chopper
which can be used when writing.
There are two different methods of writing on the disc: direct
and chopped. In direct writing, incoming pulses are written directly on
the disc. Pulses of 100 ns width are written in this mode giving about
-32-
5MHz response or about 500 line resolution. In the chop mode, the in-
coming signal is chopped by the internal chopper. Chopping is required
when it is desired to write wide pulses onto the disc as is required in
the coloring of a large area. This is necessitated by the fact that the
read mechanism is by means of detecting a changing megnetic flux on the
disc. Thus, if the flux is not continually changing there is no output.
In the Tricolor Cartograph the chopper period is about 350 nsec. corres-
ponding to 2.9MHz. This is quite close to limit specified for the disc
(100,000 points or 3MHz ) . At frequencies above this, the output de-
creases rapidly. A 350 nsec. period yields 15^- cycles per line or about
300 line resolution. In addition, the chopper is arranged to produce a
dot interlace pattern. This is accomplished by using opposite phases of
the chopper during alternate fields. This requires that the chopper start
each horizontal line in the same phase during any one field. Although the
chopper is quite stable, variations in the drive pulse frequency due to
sync track variations make it difficult to maintain the dot interlace •
pattern over an entire frame. A shift of only 175 nsec. is sufficent to
completely reverse the phase of the chopper with respect to an adjacnet
line (which occurs l6rns later in time). This is a 0.001% variation. Of
course a shift of any multiple of the period results in restoration of the
proper phase at that point. The result of this is to produce a "beat"
frequency pattern on the screen. In the present system, this non uniformity
of the dot pattern is not of great consequence since it is reasonably stable
over a period of a few minutes which is all that is required for coloring.
For a system requiring long term stability, both of the above
problems can be eliminated by recording a chop track on the disc.
-33-
k.6 The Processor
The Processor consists of a three card-rack unit containing all
the control logic and video processing circuitry. The logic is performed
with Texas Instruments Series 7^N transistor-transistor logic elements.
The video circuitry is composed of discrete components. The various op-
erations controlled by the Processor are: the total erase mode, the k
pen modes and the coloring mode. These will be discussed briefly in the
following sections. Detailed circuit and logic descriptions will be found
in the Appendix. For all modes the color or colors on which a given oper-
ation is to be performed is determined by three color selector buttons . One
may select red, green, blue or any combination of these. (7 combinations)
k.6.1 The Total Erase Operation
There are two erase operations: Color Erase and Outline Erase.
In the Color Erase operation when the Color Erase button is depressed,
an erase signal is applied to the disc tracks corresponding to the chosen
color (s) for a duration of one frame.
For the Outline Erase operation, the erase signal is applied to
the outline track for one frame.
These operations result in the disc surface at the track in
question being magnitized in one direction for the entire frame. This
causes all previously stored information to be removed.
k.6.2 The Pen Modes
There are five pen modes: Color Erase, Outline Erase, Color
Write, Outline Write and Color. The latter is explained in Section k.6.3.
In the Color Erase mode, the pulse generated by the pen is used
to drive the disc erase inputs for the colors chosen. This results
•3k-
in the erasure of points from the corresponding disc tracks.
In the Outline Erase mode the pen performs a similar operation
on the outline track.
In the Color Write mode the pulse generated by the pen is used
to drive the disc write inputs for the chosen colors. This results in
points being written on the tracks corresponding to those colors .
Similarly, in the Outline Write mode the pen writes points on-
to the outline track of the disc.
In all of the above modes the pen can be used to do free hand
writing and erasing on the color display. The Outline Write mode is
used to draw the outline of shapes which are to be colored. In the
Processor the video from the outline memory is added equally to all three
of the color video signals, red, blue and green. Thus on the display the
outline appears white. Before the outline video is added to the red,
green and blue video signals, it is delayed in order to compensate for
delays which occur in the coloring operation. If this is not done, the
colored areas are misregistered slightly from the outline.
h.6.3 The Coloring Process
As mentioned previously, the method used in accomplishing the
coloring of closed areas is a compromise between the various conflicting
requirements imposed on the system. First, there are no shades of gray
in the present system. The introduction of shades of gray into the system
allows a much wider choice of colors to be displayed. However, since it
is an operator choice, the large number of possibilities would necessitate
some sort of preview method which would allow the operator to adjust for
the saturation of his choice and then store it. The disc memory used
allows only a limited gray scale and would thus limit the usefulness of
-35-
this capability. In addition, this feature is just an extension of the
present system and does not change it in principle.'
Second, the coloring as accomplished in the Tricolor Cartograph
results in a misregistration of the color information by two television
lines vertically.
The coloring method used is best described in reference to
Figures 9 and 10. Initially the pen is pointed to some interior point
like X in Figure 9 and the enable button is depressed. When the pen
pulse is received by the processor, it begins a search for the bottom
point, B, and the top point, T. These points correspond to the points on
the outline whose horizontal location is the same as the horizontal pen
location. The processor stores the location of the closest points above
and below the initial pen location which satisfy the above conditions.
In other words, it determines the nearest points of intersection of the
outline with a line drawn vertically through the original pen point.
Having determined these points the processor uses them as the vertical
extremities of the area that will be colored during the current operation.
It is now necessary to determine the horizontal extremities. This is
done as the lines are being scanned. During any one line, the processor
simultaneously performs two operations. First, it determines the last
boundary point prior to the pen locations and the first point after the
pen location. Second, it colors between similar points which were deter-
mined on the previous line. This is shown in Figure 10. Thus, there is
a misregistration of two lines. Because the lines are very close together,
this does not produce any deterioration in the quality of the picture
while at the same time it allows the completion of an entire coloring op-
eration in about two frames (1/15 second) .
-36-
X = Pen Location
T =Top Point
B = Bottom Point
Figure 9. Top and Bottom Point Location
-37-
A = Points used to color the line given by o
Figure 10. Left and Right Point Location
-38-
Note that for a multiply connected region as shown in Figure >
and 10, no coloring is done on the side of an interior area away from the
pen point. Also, for some figures such as the one shown, it is necessary
to move the pen to several locations in order to completely color the
entire interior. Thus, to color the figure shown in Figure 9j "the pen
would have to be moved as shown in Figure 11. For the method used, the
worst case is a narrow boundary which is at 45 to the scan.
During the frame in which the coloring is done, the processor
starts at the pen location and colors the lower half of the figure during
the first field. It then colors all of the figure during the next field.
Finally it colors the top of the first field and stops when it reaches
the pen position again.
The sequential operations of the processor during the coloring
operation are shown in Figure 12. The cycle is initiated by the pen
pulse at 1. The pen pulse corresponds to the output of the light sen-
sitive pen and occurs, in time and space, somewhere inside of the closed
boundary whose interior is to be colored. With the occurance of this
pulse, the horizontal and vertical pen coordinates are stored in the hori-
zontal and vertical pen position registers. At the same time, subsequent
pen pulses are locked out for the next seven fields or until a coloring
operation is complete at which time a new cycle can be inititated. These
operations are indicated at 2 in Figure 12. The counter which counts out
the seven fields is shown at 3« This counter terminates the process if
no top and bottom point are found within the 7 fields allowed. When both
a top and bottom point are found, this counter stops. At h the search
for the bottom points begins. This is done by finding the first coin-
cidence between the outline and the horizontal pen position which was
stored previously. This search is indicated at 5 and occurs when no
bottom point has been found. At 6, the vertical drive pulse occurs
-39-
Figure 11. Coloring the Entire Figure
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Figure 12. Timing Diagram for Coloring Operation
-lH-
signifying the end of a field. This signal indicates the beginning of the
top point search and the end of the bottom point search. (Again assuming
that no top point has been found on a previous search.) The top point
search is shown at 8. For the top point, all successive coincidences
between the outline and the horizontal pen position are accepted, each
one taking precedence of the previous one. This process terminates at 9>
8-bit vertical pen coincidence, with the last top point prior to the
vertical pen coincidence being retained. The pen coincidences referred
to are obtained from a coincidence circuit which produces an output pulse
each time the horizontal and vertical counters contain the same count as
that previously stored when the pen pulse occurred. Thus, at 10, assuming
that both the top and bottom points have been found, the top point register
contains a count corresponding to the TV line on which the outline last
had a coincidence with the horizontal pen position prior to the vertical
pen coincidence. Similarly, the bottom point register contains a count
corresponding to the first line after the vertical pen coincidence on
which the outline had a coincidence with the horizontal pen position. If
both the top and bottom point have not been found the process repeats
starting at h. Assuming that both a top and a bottom point have been
found during seven or fewer fields, the process continues at 11. There
are two different vertical pen coincidences used in the system: an 8 bit
vertical pen coincidence and a 9 bit vertical pen coincidence. The 8
bit coincidence occurs every field whereas the 9 bit coincidence occurs
every frame. At 11 the system waits for a 9 bit vertical coincidence
before beginning the coloring. This is done only as a convenient means
of reference for performing one frame of coloring. Thus
-42-
from point k to point 11 a possible n fields has occurred (n < 7). Note
that the system accepts a top and bottom point from either field. At 12
the coloring begins. 13 and Ik represent the operation of finding the
left point and right point between which the coloring is to be done. Since
there is a one line delay between finding these points and using them, no
coloring is done on the first line and the choice at 15 on the first pass
is "no." After this, horizontal drive occurs at 18 signifying the end of
a line. Should the next line happen to be the line containing the bottom
point, the system awaits vertical drive before coloring the top half of
the picture. Assuming, however, that the bottom point has not been reached,
the loop returns to 12 and proceeds through 15, 16, and 17 using the
points previously found at 13 and Ik. Of course there is no delay on
passes other than the first. The left point and right point are deter-
mined in a manner similar to that used in determining the top point and
bottom point. For the left point, the system accepts all outline points
beginning at the left end of the line and retains the last one when the
horizontal pen coincidence occurs. For the right point, the system retains
the first outline point occurring after the horizontal pen coincidence.
At point 20 then, the bottom of one field has been colored. Just as there
is a one line delay in starting the coloring, the coloring stops one line
prior to the bottom point. Thus the coloring is actually done inside of
the outline. After vertical drive at 20, a process similar to that for
the bottom of the. figure is carried out for the top of the figure. The
major difference is that the test at 29 is for 8 bit vertical coincidence.
When an 8 bit vertical coincidence is obtained, a check is performed at
30 for a 9 bit coincidence. On the first field there will be none and
the loop returns to 12 where it colors the other field for the bottom of
the figure. Then at 19, 20 and 21 the coloring of the other field for the
-h3-
top of the picture is begun. Finally at 30, a 9 bit vertical coincidence
occurs and after waiting for the next horizontal drive pulse (indicating
the end of the current line) the process stops and is ready to begin again
at 32. The time elapsed from C to D is one frame in length (l/30 second).
At this time if the pen Enable switch is still activated and the pen is
in the repetitive coloring mode, a new pen positon is accepted and the
process begins anew. In the single coloring mode, the Enable switch must
be released and reactivated in order to initiate a new coloring cycle.
During vertical retrace, the left and right point registers are
set equal to the pen position. This is done so that extraneous coloring
will not occur should the system fail to find a left or right point at the
top of the figure. Failure to find a point can result from there being no
point to find on a particular line or because of the outline geometry at
the top of the figure. In Figure 13 A and B, either the right point or
the left point is coincident with the horizontal pen position. Under
these circumstances, the system may fail to find either the right or left
boundary. Since the system always uses the last retained left or right
point unless a new one is found, failure to find the boundary at the top
means that the left or right point which was used at the bottom will be
used at the top. Except in special cases, these points are wrong and
frequently can result in coloring outside of the outline. By initializing
to the pen position, the coloring is kept within the boundary.
The location of points on the raster of the system are deter-
mined by means of a horizontal and a vertical counter. The horizontal
counter counts the output of an oscillator which operates at about 8MHz.
This oscillator is voltage controlled so that its frequency varies with
disc speed changes 'which occur over time of the order of a frame. Precise
tracking is not necessary since stability is not necessary for more than
about one line (63 • 5 l-t sec). The variation in disc speed during this
-kk-
Top of outline
Horizontal
pen position
A. Possible failure in finding right point
No other boundaries
to the left — <JTbp of outline
Horizontal pen position
B. Possible failure in finding left point
Figure 13 . Errors in Finding the Right and Left Points
-k5-
time is about 70 nsec. maximum. The horizontal counter is reset at the
end of each line by the horizontal drive signal. Thus, the count is
initialized to zero at the start of each line. This produces a maximum
uncertainty between two successive lines of 62 nsec. (1/2 of the clock
period) due to the uncertainty of the start of the counter. Considering
this with the variation in disc speed gives a maximum variation of 2
counts per line which is less than the resolution of the system.
The vertical counter counts the horizontal drive pulses and is
reset by the vertical drive pulse. The least significant bit of the
vertical counter is controlled by the horizontal counter in conjunction
with the vertical drive pulse. The horizontal counter supplies a signal
during the center two quarters of each horizontal line. Depending on
whether this signal is present or not when the vertical drive pulse occurs,
the least significant bit of the vertical counter is either set to a
logical zero or one. Thus the least significant bit determines whether
the vertical counter contains an even or odd count corresponding to an
even or odd field. The scale of the remainder of the vertical counter
which counts horizontal drive is then two.
Coordinates corresponding to positions on the display are
stored as counts in the various registers. There are five horizontal
registers and three vertical registers. Some of these registers are
combined with coincidence circuits such that when the register count
corresponds, to the counter count an output pulse is generated.
The horizontal registers are the horizontal pen register, the left
point register (dual) and the right point register (dual) . The horizontal
pen register stores the horizontal coordinate of the pen position. The
upper level of the left and right point registers store the left and right
point coordinates to be used in coloring on the following television line.
-k6-
The lower level of these registers contains the currently used left and
right point coordinates . The inf ormation in the upper level is shifted
into the lower level during horizontal drive. Both lower left and right
point registers as well as the horizontal pen register have a coincidence
output .
The vertical registers are the vertical pen register, the top
point register and bottom point register. The vertical pen register con-
tains the vertical coordinates of the pen position. The top and bottom
point registers contain the vertical coordinates of the top and bottom
point. All of these registers have coincidence outputs. Figure Ik shows
a simplified diagram of the coloring logic. The complete coloring logic
may be found in the Appendix. As can be seen in Figure Ik, the actual
color signal used to write on the disc is the result of Anding the hori-
zontal and vertical color duration signals.
In the simplified diagram of Figure 1^, the horizontal pen register
and coincidence does not perform any function. In the actual system it
is used in determining the initial starting and final stopping of the
coloring. Its primary function, of course, occurs during the search for
the top and bottom points. The coincidence is a seven bit coincidence
rather than a 9 bit coincidence so as to provide a fairly wide window
during the search for the top and bottom point. This increases the
probability of finding a coincidence. The coloring circuitry as well as
the top and bottom point search control logic is discussed in detail in
the Appendix.
-hi-
\ ,
Right Point
Register and
Coincidence
I *
a
10
M
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Figure lU. Simplified Diagram of Coloring Logic
-Ii6-
5. DISCUSSION OF RESULTS, SUGGESTED IMPROVEMENTS AND CONCLUSIONS
Only one unforseen problem occurred in the final system. This is
the so - called "bleeding problem. " Recall that one of the rules for the
boundary is that it must be closed. In the event that it is not closed
(i.e. if there is a hole), the coloring logic will not find a boundary
point at that location. This is usually no problem since under these
circumstances the system reuses the point which it used previously. Since
the boundaries are usually slowing varying and contain only a few holes,
no misregistration of the coloring results. If however, there is another
boundary present which is not a part of the boundary in question but
which does have a point on the particular line being considered, the
system will then take this point to be the boundary. This causes the
color to "bleed" through the hole in the outline. This is shown in Figure
15. Of course this is precisely what the system is supposed to do, but
it is usually not what is desired by the operator.
The problem arises because of the pen writing method used. Since
the pen signal is generated by light from the raster, the pen produces a
signal at a very low repetition rate (one pulse every 1/60 second). In
practice it is easy to move the pen past more than one raster line in
this time and thus "skip" some lines. This leaves holes in the outline.
These holes cause no problem, of course, if the outline is simple. For
multiple outlines however these holes cause faulty coloring. Prevention of
holes requires considerable care in drawing the outline. One solution
to this problem is to use some other method of generating the pen signal
which will yield a higher pen pulse rate. This is not a very useful
approach, however, since the disc can be written on only at the 1/60 pulse
per second rate. Another solution is to utilize some kind of gap filling
scheme. A third is to allow only one outline to be drawn at a time. The
best solution is the second one if it could be implemented.
-1*9-
Figure 15. The Bleeding Problem
-50-
A related problem which occurred was that of leakage at the top
and bottom. This occurred because of the difficulty in drawing a hori-
zontal boundary with the pen. When a horizontal line is written with
the pen, if many pulses are written at a high density, the disc becomes
magnitized completely in one direction and the output begins to decrease.
When this happens gaps appear at the top and bottom of the figure's
boundary. If another boundary occurs above or below the gaps, the top
and bottom point search may "slip through" the gap and find the wrong top
or bottom point. This is shown in Figure 16. This problem can be elimi-
nated by careful use of the pen in the horizontal direction and by widening
the top and bottom point search window so that the probability of a point
occurring within the window is increased.
As mentioned before, neither of the above problems manifests
itself if the outline is accurately drawn or sufficiently simple. To be
simple enough requires that there be only two outline points on any one
horizontal line. This is frequently not the case, of course.
It is possible to take advantage of the fact that if no new
left or right points are found, the old ones are reused in this system.
One can easily color any square or retangular figure by simply designating
a top point, a bottom point and any left and right points which are required.
In other words, it is not necessary to completely close the figure (if it
is the only figure). It is only necessary to designate one top and one
bottom point which lie on the same vertical in order to define the extent
of the figure in the vertical direction. To define the horizontal extent
it is sufficient to designate a left or right point only on those lines
for which the horizontal width of the coloring is to change. Of course,
the first horizontal line must be defined unless one desires the coloring
to be only as wide as the initializing circuitry permits. Clearly, this
only works for figures which are aligned with the scanning line.
■51-
Top Leakage
Bottom Leakage
Figure 16. Leakage Through a Gap
-52-
There are some changes which could possibly yield improvements
in performance in future devices like the Tricolor Cartograph. Stabilizing
the disc speed -would allow more stable operation of the display and the
processor. As mentioned above, perhaps some other type of pen could be
used to advantage in order to improve the type of outline which is obtained.
Possibly outlines could be input directly from a television camera which
is synchronized to the disc. Then line drawings of things to be colored
could be made with black ink on white paper and input by this means. In
addition, an automatic erase feature could be implemented so that selected
areas can be automatically erased just as they are automatically colored
now. A higher resolution disc would, of course, yield a higher quality
picture and allow the use of a higher chopping frequency. The use of a
higher chopping frequency would give a more uniform colored area. If a
high frequency chopping signal can be recorded on the disc, the problem
of maintaining the dot interlace over the entire frame can be eliminated.
This would be accomplished by recording the interlaced chopping signal
right on the disc. Then the horizontal and vertical drive signals could
be generated from this chop track by using counters or a separate sync
track which is synchronized to the chopping track could be used. Finally,
the addition of shades of gray would, of course, add more variety to the
colors obtainable with the system.
The Tricolor Cartograph proved itself to be a very successful
investigation. The coloring method used, although it results in a two
line misregistration, results in very adequate colored areas. The mis-
registration which occurs is not noticable. The concept of using a local
storage media which is capable of storing large amounts of pictorial
coloring information was demonstrated to be feasible. Assuming further im-
provements in resolution, the disc appears to be an ideal storage media for
-53-
this purpose. Also demonstrated is the concept of performing a reasonably-
complex operation, the coloring of closed areas, at a display console as
opposed to performing a specialized operation such as this with a general
purpose digital machine. In addition, the automatic coloring was imple-
mented in a reasonably simple manner. Improvements in the resolution of
discs and reductions in the complexity of color display tubes in the next
few years will make moderate cost high resolution color display terminals
with special purpose processing capabilities a useful reality.
-5U-
APPENDIX
-55-
Al.O LOGIC DESCRIPTIONS
Al.l Control and Video Logic
Figure 17 shows the Control and Video logic except for the
coloring logic which will be discussed in Section A1.2.
All control signals and power enter on J31. The control signals
originate at the push buttons on the front of the display console. These
control signals, except the Outline Erase and Color Erase signals, go to
the Switch Matrix logic A-l where they are combined to form the required
signals for writing and erasing in the appropriate color. An example
would be the erase red signal, R(ER), where ER indicates pen erase or
total erase. The Total Erase Control A3 generates a one frame gate pulse
for erasing an entire track of the disc. The Total Erase Control circuit
is triggered by either Cl-1 for the Color Erase operation or Cl-U for the
Outline Erase operation. An explanation of the Total Erase Control
circuit will be found in Appendix Section 2.1. The outputs of both of
these circuits, Al and A3, provide signals to the logic which drives the
Logic to Video Converters A4 and A10. Ak and A10 drive the four erase
and four write inputs to the disc. The pen pulse enters the control at
J23 and is shaped at A15. It then passes to the video adders A19, 20
and 21 as well as to the video to Logic Converter AI7. At the Video Adders
A19, 20, and 21, the pen signal is added into the red, green and blue video
signals so that it will be displayed on the monitor screen as a white
reference dot. At AI7 the video pen pulse is converted to a logic pulse
so that logic operations may be performed on it. The logical pen pulse
ultimately performs two functions: writing or erasing in the memory and
initialization of the coloring operation. The enable signal from the pen
enters at J31-T and passes through A3 where it is locked out during total
erase. From A3 it proceeds to Cl-9. This is a delay flip flop which
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Figure 17. Control and Video Logic
-57-
delays the opening of the pen gate until the switch noise from the Enable
switch has passed. This is necessary since the pen' preamplifier is satur-
ated by the switch noise thus producing spurious pen pulses. After delay,
Cl-12 is triggered. This sets pen gate flip flop (l) allowing pen pulses
through gate A13-C. Flip flop (2) prevents successive coloring operations
even though the enable button may be depressed when the single multiple
switch is in the single position. Vertical and horizontal drive enter at
ji+5 and Jh6 respectively and are converted to logic levels by the level
shifters Bl-2 and 7- Control of the chopper is performed by the mode
switch A8-7. The chopper is normally activated when a pen pulse is re-
ceived in the color mode of operation. It can, however, be activated by
placing the Set-Up, Operate switch in the Set-Up position. This allows
the chopper to be run for adjustment purposes.
The video signals for the monitor originate at the red, green and
blue video adders, Aly, 20 and 21. Here the red, green and blue video
signals from the disc entering at J^O, kl and h2. are added to the pen
pulse from the pen shaping circuit and the outline video signal coming
from the disc at J^3» This allows equal signals from the pen and the out-
line memory on each of the three colors and thus they appear white on the
display. The outline video entering at Jl+3 passes through a delay line
before going to the adders. The undelayed signal passes directly to the
Video to Logic converter AI7-IU where it is converted to logic levels and
used in the. coloring logic. The delay is required in order to bring about
registration of the outline with the colored interior of the outline. With
no delay, the interior lags the outline due to delays in the coloring
circuitry.
B2 is the horizontal oscillator, B3 the horizontal counter and Bk
the horizontal buffer. Similarly, BlU is the vertical counter and B15
the vertical buffer. The outputs of these two buffers drive the inputs of
-5*
all the register and coincidence circuits used in the coloring logic. The
least significant bit from the horizontal buffer also goes to gate A7-10
where it chops the pen signal when writing a color. This helps alleviate
the problem of overrecording when writing in a color with the pen. This
is not done in the outline writing mode because it interferes with the
writing of a good outline. See the discussion of pen problems in Section 5,
The Horizontal Oscillator produces an 8MH clock signal which is
counted by the Horizontal Counter. This signal appears at B2-B and enters
the counter at B3-13* Horizontal drive enters the counter at B13-12. It
is used to reset the counter each horizontal line. The Horizontal Counter
produces two signals in addition to the 18 flip flop outputs. The first
of these is the AFC pulse. This pulse is fed back to the oscillator to
provide some degree of frequency control. The second is the field sync
pulse. This signal goes to the Vertical Counter where it controls the
state of the least significant bit of that counter. This is done so as to
keep the Vertical Counter referenced to the proper field of the television
frame. The field sync pulse is the logical exclusive-or of the two most
significant bits of the Horizontal Counter. This pulse then exists during
the center two-fourths of each television line. If the vertical drive
pulse occurs during this field sync pulse, then the next field is even
and the least significant bit is set to zero. If the vertical drive pulse
occurs other than during the field sync pulse, the least significant bit
is set to a one to indicate the beginning of an odd field.
The signal appearing at B2-D is the clock signal of the Horizontal
oscillator but it is shifted in phase 180 from the signal driving the
counter. This signal is used in the coloring logic in order to accomplish
synchronous dumping of the contents of the Horizontal Counter into the
horizontal registers.
-59-
The Vertical Counter (with "Che exception of the least significant
bit) counts the horizontal drive pulses from the disc. The vertical drive
pulse causes this counter to reset at the end of each field.
The 7 bit Vertical Pen Register and Coincidence circuit and the
9 hit Horizontal Pen Register and Coincidence circuit provide output
pulses which indicate the last horizontal and vertical position of the
pen. This output is not used at present.
The Indicator A2 provides an indication that the control signals
generated at the Display Console have been properly received at the
Processor.
Al. 2 Coloring Logic
The coloring logic is shown in Figure 18. The coloring logic is
a mixture of synchronous and asynchronous logic. As described in Section
k.6.3) there are five horizontal and three vertical registers. The hori-
zontal registers are B7 (dual register), B8, BIO, and Bll. The dual
register B7 stores the left and right boundary points as they are found.
These are then shifted into the register and coincidence circuits B8 and
BIO whose outputs control the Horizontal Color Duration flip flop (8) .
This flip flop controls the length of the coloring in the horizontal
direction. It is set by the output of the Horizontal Left Point Register
and Coincidence circuit B8. It is reset by the output of the Horizontal
Right Point, Register and Coincidence circuit BIO. It can also be reset
by horizontal drive if for some reason the right point coincidence fails
to occur. This prevents the coloring from continuing beyond the end of
the current line .
Since a left point cannot occur to the right of a right point, (8)
cannot be set once the right point has been passed. This is accomplished
at C2-2 by means of flip flop (20). Flip flop (20) is reset by hori-
■6o-
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Figure 18. Coloring Logic
-61-
zontal drive and set by right point coincidence. In addition to this
signal, flip flop (8) also cannot be set during horizontal drive (when
the registers are changing) or while it is being reset (as might occur
when the left and right points are the same). These two functions are
accomplished at C2-5 and C2-6 respectively.
Register Bll is the Horizontal Pen Register and Coincidence circuit.
This register stores the horizontal coordinates of the light pen during
the coloring operation. In addition, a pulse is generated by it each
time the contents of the horizontal counter is identical to the contents
of the register. This output pulse fulfills several functions in the
system. First, it is used to initialize the Left and Right Point Registers
during vertical drive. This is accomplished at B6-X and N and Cl-T and
B6-13. The pulse sent to the Right Point Register is delayed from that
sent to the Left Point Register by using the inverted coincidence signal
(B9-16) in conjunction with the One Shot Cl-15. By delaying the right
point, the left and right points are prevented from assuming the same values.
This in turn prevents uncertainty in the state of the Horizontal Color
Duration flip flop should the system fail to find a left and right point
at the top of the colored area. The second function for which the Hori-
zontal Pen Coincidence is used is in the determination of the top and
bottom points. This is done at C^-M, N, P and C4-V, U and W. At these
two gates the outline pulses which are coincident with the horizontal pen
coincidence- are channeled to the appropriate storage flip flop (3) or {h) .
Which of these flip flops is set is controlled by the Point Search Control
flip flop (2). This flip flop controls whether the top point gate or the
bottom point gate is open. Once a bottom point is found, the appropriate
flip flop, (3) is set and no further search for that point takes place.
-62-
This is accomplished by having the flip flop itself close the gate. For
the top point, the gate is not closed until a top point is found (signified
by (k) being set) and the 8 bit vertical coincidence occurs. In this way.
all points are accepted starting from the top of the picture on down
until the vertical pen position is reached. The top point search ceases
when flip flop (5) is set. The pulses which set the top and bottom point
flip flops also dump the vertical counter into the top and bottom point
registers B-19 and B-l8. If a top or bottom point signal has not been
found when the counter Cll times out, the No Bottom Point or No Top Point
flip flops (15) and (16) are set and appropriate indicators light showing
why the coloring failure occurred. The Point Search Control flip flop
(2), as mentioned earlier, controls which point is being sought. This is
accomplished by having this flip flop in the set state between vertical
drive and vertical pen coincidence (upper part of figure) and having it
in the reset state between vertical pen coincidence and vertical drive
(lower part of figure). The two outputs control the routing of the co-
incidence pulses to the appropriate registers and flip flops. This coin-
cidence signal is generated at C2-A, B, E, F, and D. At this gate the
logical Nand of the start flip 1, the horizontal pen coincidence, the out-
line and the not side of the End Point Search/Begin Coloring flip flop is
formed. The essential combination is that of the outline and the hori-
zontal pen coincidence. The other signals are present for control purposes.
Flip flops. (7) and (9) control the left and right point dump. These
flip flops are both reset by horizontal drive. When a line is scanned,
the Left Point Stored flip flop remains reset until the horizontal pen
coincidence occurs. During this time any outline pulse which occurs
causes the Horizontal Counter to be dumped into the Left Point Register
B7 by the Left Point Dump flip flops 18 and 19. Once the horizontal pen
-63-
coincidence has occurred, (7) is set and outline pulses are allowed to
pass to the right point logic. The first pulse after horizontal pen co-
incidence causes the right point dump flip flop (17) to dump the hori-
zontal counter contents into the Right Point Register B7. At the same
time (9) is set and the right point gate is closed. The flip flop (17)
stores the fact that a right point has occurred. On the next clock pulse
after (17) is set, the counter is dumped into the register. This synchro-
nizing circuit is required to prevent the counter from being dumped while
its contents are changing. The left point dumping circuit (l8 and 19)
is more complicated than the right point dumping circuit. This is because,
whereas there is only one right point, there is a whole succession of
left points the last of which must be retained. Thus flip flop (l8) ac-
knowledges the occurrence of a left point and sets flip flop (19) while
at the same time locking out future pulses. (19) remains set until the
next clock pulse at which time the left point is dumped and both (l8) and
(19) reset so that the next pulse can be accepted. Because of the high
speed of the horizontal counter it is necessary that the horizontal
registers be filled synchronously. This is not the case with the vertical
registers and they are filled asynchronously.
As mentioned, there are three vertical registers: the Vertical
Pen Register Bl6, the Vertical Bottom Point Register Bl8 and the Vertical
Top Point Register B19. These are all 8 bit registers with 8 bit coin-
cidence outputs. The Vertical Pen Register stores the vertical coordinate
of the pen position and gives a coincidence pulse whenever its contents
are identical to the vertical counter. Since the vertical registers are
all 8 bit registers, the coincidence pulses produced by them occur every
field. A 9 bit coincidence is formed at C5-P by using the coincidence of
the least significant bit and the output of the 8 bit coincidence circuit.
-6k-
The 8 and 9 bit Vertical Pen Coincidence signals are used to perform
various control operations in the system. The coincidence outputs of the
top and bottom point registers control the Vertical Color Duration flip
flop (10). This flip flop is set by vertical 9 bit coincidence or vertical
drive or vertical bottom point coincidence. In its normal sequence of
operation it is set first by a 9 bit vertical coincidence whereupon the
bottom of the figure is colored. Next it is reset by bottom point coin-
cidence. Then it is set again by top point coincidence (the other field)
and reset by bottom point coincidence. Finally, it is set by top point
coincidence and then the whole process is terminated at 9 bit vertical co-
incidence again. Flip flop (21) prevents the Color Duration flip flop (10)
from being set if the bottom point has already been passed. In addition,
the set input is locked out by the reset input and the flip flop is reset
by vertical drive. These three precautions are necessary to prevent
erroneous coloring if the top and bottom point positions should become
interchanged, i.e. the top point is below the bottom point.
Now that the individual functional groups of the coloring logic
have been explained, a description of one complete coloring cycle will be
given. This will explain the sequential operation of the system and
indicate the function of the control logic as yet unmentioned.
The cycle starts with a pen pulse at B6-5- This causes the
horizontal and vertical coordinates of the pen to be stored in the hori-
zontal and vertical pen registers Bll and Bl6. At the same time the Start
flip flop (l) is set and the Stop flip flop (lU) is reset. Setting the
Start flip flop opens gate C2-ABEDF allowing outline pulses which are co-
incident with the horizontal pen position to pass to the top and bottom
point search logic, explained previously. It also locks out future pen
-65a-
pulses and triggers the one shot Cl-6 which resets the No Top Point and
No Bottom Point flip flops. The Stop flip flop closes gates C9-13, Ik,
12 and C9-15, 16, 17. Thus stopping the flow of reset pulses which have
kept flip flops 1, 2, 3> ^-> 5, 6, and 12 as well as counter Cll reset.
At the same time it allows counter Cll to commence counting vertical drive
pulses . Recall that Cll allows 7 fields for finding the top and bottom
points. If no top and bottom point are found in 7 fields the entire pro-
cess is terminated by the signal at C10-L which gates the proper infor-
mation into the No Top Point and No Bottom Point flip flops at C8-S and R
and resets the Stop flip flop at C9-P. If both the top and bottom points
are found a signal is generated at C8-E. This signal stops the counter
Cll at CIO- 20 and allows flip flop (6), the End Point Search /Begin Coloring
flip flop to set at the next 9 bit vertical coincidence. This flip flop
closes gate C2-ACEDF and locks out its own set input. It also opens gates
C8-3, k, 5 and C8-6, 7, 8. The signal at C8-3, h, 5 causes the Vertical
Color duration flip flop (10) to set for the coloring of the lower half
of the figure as explained previously. The signal at C8-7 allows the next
vertical drive pulse to set flip flop (13) , the Field Lapse flip flop.
This flip flop simply senses the fact that one field has elapsed since
the flip flop (6) was set. In other words it inhibits pulses at C10-F
until both fields of the frame have been colored. The vertical color
duration logic operates as explained previously. The Vertical Color Dur-
ation flip flop (10) opens gate C8-9, 10, 11. This allows flip flop (11),
Horizontal Line Lapse to be set when the next horizontal pen coincidence
pulse occurs. It also opens gate C3-CDE allowing outline pulses to pass
to the horizontal color duration circuitry. It also has the effect of
removing the reset signal from flip flops (11) and (12). Once (11 ) has
been set, (12) will be set by the next horizontal drive pulse. Thus, the
effect of (ll) and (12) is to introduce a one line delay before the actual
-65b-
coloring begins. This accomplishes two things: First, it allows the
horizontal color duration logic to find some left and right points and
second, it causes the coloring to fall within the outline. Thus, the
actual coloring signal is formed at C^-K and consists of the logical Nand
of the Color Control flip flop (12) (which is just flip flop (10) delayed
from starting by one line) and the horizontal color duration signal from
flip flop (8) as already explained. The cycle now continues under the
control of the Vertical Color Duration flip flop (10) until the next 9
bit vertical coincidence pulse occurs (one frame). This signal appears
at C10-H. After this signal is generated, at the next horizontal pen
coincidence the Stop flip flop (lU) is set. The cycle continues until
the next horizontal drive pulse at which time all the flip flops 1, 2, 3?
k, 5, 6, 11, 12 and 13 are reset. Note that (ll) and (12) are reset by
virtue of (6) being reset. During coloring, the color signal generated
at C9-K passes to A7-U, A7-N and is then routed through one or more of
the color selection gates A7-E, F, K and on to Logic to Video Converter
A10. This completes the description of the coloring logic.
-66-
A2.0 CIRCUIT DESCRIPTIONS
In this section a brief circuit description will be given for
each printed circuit board and major chassis.
A2.1 Circuit Boards
The circuit boards are discussed in order by number. The
schematics of these circuits are given at the end of this section. All
digital integrated circuits are Texas Instruments Series 'jk'N.
1^69-121 Pen Preamplifier
This is a two stage high pass, high gain amplifier used in the
pen to amplify the output of the light sensitive diode. The Enable switch
is also located on this circuit board.
1^69-133 Counter Buffer
This circuit has 2-input nand integrated circuits connected as
inverters. It is used to buffer the output of the horizontal and vertical
counters .
Ik69-13k Horizontal Counter
A 9-bit synchronous counter utilizing J-K flip flops.
11+69-135 Dual 9-Bit Register
A dual 9-t>it clocked register utilizing D-type flip flops.
1469-136 8-Bit Register and Coincidence
An 8-bit clocked register utilizing D-type flip flops whose out-
puts are connected to a digital comparator circuit which utilizes And- Or -
Invert type logic circuits .
-67-
1469-137 R-S Flip Flop
Several nands connected to form R-S flip flops.
IU69-I38 Vertical Counter
A 9-bit synchronous counter utilizing J-K type flip flops .
1U69-139 9-bit Register and Coincidence
The same as the 8 bit circuit except with an added bit.
lk6S-lkO Switch Matrix
A decoder for the control switches which generates the logical
combinations of the control switch signals required by the processor.
11*69-11+1 2-bit Coincidence and R-S Flip-Flop
Several nand connected as R-S flip flops as well as a D-type
flip flop and And-Or-Invert circuit connected as a 1 bit register and
comparator. Used to form a 9-t>it coincidence from an 8-bit coincidence
and a 1 bit input.
1469-11*5 Total Erase Control
Logic to generate a one frame erase signal as well as perform
certain lockout functions.
1U69-156 Level Shifter
Shifts the video drive signals (about-1* volts) to logic levels
(-5 volts) .
11*69-159 One Shot Buffer
A group of nands connected as monostable multivibrators . Both
a complemented and an uncomplemented signal are available.
-68-
Ik69-l6l General 2- Input Nand
Three 2- input nand packages with all pins' brought out.
1U69-162 General 3- Input Nand
Three 3-input nand packages with all pins brought out.
1U69-173 Switch Filters
A group of RC low pass filters for the control switches.
1^69-175 Logic to Video Converter
A very fast direct coupled switch which converts the -5 volt
to volt logic levels to a 9 to +1 volt video level.
1^69-176 Indicator
An array of 9 light bulbs with drivers such that a zero volt
signal lights the bulb and a -5 volt signal extinguishes it.
1469-177A Video to Logic Converter
A very fast, very high gain direct coupled level shifter with
adjustable input threshold which will convert a to +0.3 volt video
signal to a to -5 volt logic signal.
li+69-178 +1 Volt Supply /Mode Switch
Supplies +1 volt and provides a switch which converts the logic
level input to the level required by the chopper control input on the disc,
1U69-179 Pen Shaper and Gate
Converts the pen pulse into a very fast +1 volt pulse about
100 nsec wide. Also provides a logic gate output which begins with the
pen pulse and lasts for several hundred^ seconds.
-69-
1469-180 3- Input Video Adder
This circuit combines three separate video input signals into
one. Separate gain adjustment is provided for each signal as well as
overall gain. It is direct coupled and wide band.
1469- l8l- 20 General 4- Input Nand
Three 4- input nand packages with all pins brought out.
l469-l8l-70 General J-K Flip Flop
Three J-K Flip Flop packages with all pins brought out.
1469-184 Voltage Controlled Oscillator
A Colpitts oscillator with a varactor diode in the tank circuit,
A pulse width to voltage converter produces a control voltage dependent
on the incoming pulse width. The maximum shift is about 15 kHz /usee and
is adjustable by means of the gain adjustment.
A2.2 Chassis
The following is a brief description of each of the major
chassis. Following the descriptions the schematics are shown.
A2.2.1 Main Junction Box
The Main Junction Box serves as a control and power distri-
bution center for the Main Console.
A2.2.2 Display Junction Box
The Display Junction Box serves as a control and power distri-
bution center for the Display Console. In addition the pen thresholding
and amplifying circuit is located in it.
-70-
A2 . 2 . 3 Miscellaneous
The other major major chassis are the Circuit Breaker Panel,
the Modular Power Supplies and the Switch Panel. The Circuit Breaker
Panel serves as an AC distribution point. The Modular Power Supplies
provide -5, +10, and +25 volt DC sources for all of the circuitry. The
Switch panel contains the Control Switches which are used to select the
operating modes of the system.
1469-121 PEN PREAMPLIFIER
-71-
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in
m
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Figure 20. Counter Buffer 1U69-133
-73-
Figure 21. Horizontal Counter -1469-134
- 7 k-
000000000®
s l
2 5
Figure 22. Dual 9-Bit Register 1^69-135
-75-
Figure 23. 8-Bit Register and Coincidence 1U69-136
l
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Figure 2k. R-S Flip Flop II+69-I37
Ibd ■ ■ j i. j
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-77-
Figure 25. Vertical Counter 1469-138
■78-
Figure 26. 9-Bit Register and Coincidence 1U69-139
■79-
Figure 27. Switch Matrix li+69-l^O
(0
V)
Q.
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9
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-80-
■1 3M0K Vrr —
Figure 28. 2-Bit Coincidence and R-S Flip Flop lU69-lUl
(03)(,3OK
(03)(,30)^
o
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Figure 29. Total Erase Control Ik69-lh5
A.T.C. LEVEL SHIFTER 1469-156
22 pf
if
2.2 K
IN>— * VW — ii— h )
10K Vtv/
-10
10K
k 2N3905
1N482
C
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- GND
]
■82-
A.T.C. LEVEL SHIFTER 1469-156
2>
^3
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18
-10
1/2A
A.22>
.47 M f
25v
GND
.47 M f
25v
20>
^15
->-10
10>f
35 w
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35v
^-5
Figure 30. Level Shifter 1469-156
J
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Figure 31. One Shot Buffer 1469-159
1469-161 ~*0 INPUT NAND
-81+-
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FILTEHED VOLTAGE
OUT
B O-
«>-5v
NOTES
(T) JUMPERS ALLOW POSITIVE OR NEGATIVE OPERATION
2. ALL CIRCUITS TEXAS INSTRUMENTS SN7400N
Figure 32. General 2- Input Nand 1469-161
1469-162 THREE INPUT NA'ir
i
of
I _J
I 1
14
Ji
J2.
10
11
w
15
20
19
18
17
16
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FILTERED VOLTAGE
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21
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B o-
10
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NOTES
® JUMPERS ALLOW POSITIVE OR NEGATIVE OPERATION
2. ALL CIRCUITS TEXAS INSTRUMENTS SN7410N
Figure 33. General 3- Input Nand lk69-l62
1469-173 FILTER
-86-
IN o-
1
-5
330ft
— WV/ ♦
1.5K
-o OUT
.47/if
25 v
1
-5
NOTES
1. ALL RESISTORS 1/4 W , 5 % .
2. SEE NEXT PAGE FOR PIN CONNECTIONS
1469-173 FILTER
B o-
C o-
D O-
E o-
L o-
N o-
P o-
S o-
T o-
V o-
w o-
A O
22 o
GND
19 o
-5
-o 1
-o 2
-o 3
-o 5
-o 6
-O 8
-o 9
-o 10
-O 11
-o 12
-o 13
-o 14
-o 15
-o 16
-o 17
-o 18
Figure 3^. Switch Filter 1^69-173
ATC LOGIC TO VIDEO CONVERTER 1469-175
-87-
+ 10 *-
IN>
10K
-)!-
47 pf
36 K
5%,1/2W
2N3642
-5
(3)
I1N914B
2N706A
i> •
75 ±
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1N995
-± NOTE
ALL RESISTORS 1/4 W, 5%
UNLESS NOTED.
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Figure 35. Logic to Video Converter 1^69-175
ATC INDICATOR 1469-176
-88-
in y — wC — PT j
>
>
>
>
>
11
B
D
220 ft
NOTES
1. ALL RESISTORS 1/4 W, 5%
2. ALL TRANSISTORS 2N3642
3. BULBS 6v/40ma (SAME AS 1469-115)
4. SOCKETS FOR BULBS
>
13
>
16
>
18
>
21
H
5>
22
GND>-i-
1/2A
-*-5
2.2 M f
25v
GND
Figure 36. Indicator 1^69-176
ATC VIDEO TO LOGIC CONVERTER 1469- 177A
IN >-
ion
-L- 1CV
35v
+ 10
001 M f
4.7K
250pf
* — wv — *
100 n
2.2K
c
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2N709
3.9K
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- 25v 2iTI51 "
ion
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2N967
35v
-^OUT
-> OUT
^ tl^ % 1N914B^ 510
25v n
-5
NOTES
l.ALL RESISTORS 1/4 W, 5%
UNLESS SPECIFIED.
(2) DIODES AS THRESHOLD REQUIRES
IN >-
12
11
->0UT
v 20 1/2A
+ 10 >— — — ^v-
21 1'2A
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10 M f
35v
.47
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1 »• +10
.47
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10 M f
35v
GND
Figure 37- Video to Logic Converter 1U69-177A
ATC +lv GENERATOR/MODE SWITCH 1469-178
CIRCUITS ABB
+ 10 «•
. 10K
IN > » — vw
>0UT
(+2v)
■90-
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150ft
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NOTES
l.ALL RESISTORS 1/4 W ,
5% UNLESS SPECIFIED
2.2 CIRCUITS EACH PER CARD
B
(+2v)
»K
(+lv)
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1469-181-20 4-INPUT NAND
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1
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3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22-5
NOTES
1. CIRCUITS ARE TEXAS INSTRUMENTS SN7420N
Figure 1+1. General 1+- Input Nand l*+69- 181-20
1469-181-70 J-K FLIP-FLOP
A l
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C 3
D 4
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9
10
11
12
13
14
15
16
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•18
19
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ALL CIRCUITS TEXAS INSTRUMENTS SN7470N
Figure h2. General J-K Flip Flop lU69-l8l-70
1469-184 VOLTAGE CONTROLLED OSCILLATOR
-95-
iFC \l
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1 ALL RESISTORS 1/4 V» . 5%
2 INTEGRATED AMPLIFIERS ARE FAlRCMILO
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-96-
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-102-
A3.0 CAED RACK LISTS
CARD RACK A
1. Switch Matrix
2. Indicator
3. Total Erase Control
h. Logic to Video Converter
5 . Blank
6. 2- Input Nand
7. 2- Input Nand
8. +1 Volt Generator /Mode Switch
9. Blank
10. Logic to Video Converter
11 . Blank
12. Blank
13. 2- Input Nand
1^ . Blank
15. Pen Pulse Shaping Circuit
16 . Blank
17. Video to Logic Converter
18. Blank
19. 3- Input Video Adder
20. 3- Input Video Adder
21. 3- Input Video Adder
CARD RACK B
1. Level Shifter
2. Horizontal Oscillator
3- Horizontal Counter
h. Horizontal Buffer
5. 9-Bit Register and Coincidence
6. 2- Input Nand
7. Dual 9-Bit Register
8. 9-Bit Register and Coincidence
9- 2- Input Nand
10. 9-Bit Register and Coincidence
11. 9-Bit Register and Coincidence
12. 2- Input Nand
13 . Blank
Ik. Vertical Counter
15. Vertical Buffer
16. 8-Bit Register and Coincidence
17. 2- Input Nand
18. 8-Bit Register and Coincidence
19. 8-Bit Register and Coincidence
20. 8-Bit Register and Coincidence
21.
-1C&-
CARD RACK C
1.
One Shot Buffer
2.
h- Input Nand
3-
2- Input Nand
k.
3 -Input Nand
5.
R-S Flip Flop and
2-Bit Coincidence
6.
Indicator
7-
R-S Flip Flop
8.
2- Input Nand
9-
2- Input Nand
10.
3- Input Nand
n.
J-K Flip Flop
12.
Blank
13-
Blank
14.
Blank
15-
Blank
16.
Blank
17-
Blank
18.
Blank
19.
Blank
20.
Blank
21.
Blank .
-1C
A^.O OPERATING PROCEDU1 i'MENTB
To operate the Tricolor Cartograph turr. tin circuit breai
and allow to warm up for ten minutes. Before using, all tracks
disc should be erased. This is accomplished by depressing the Outline
Erase button and the Color Erase button after depressing all three color
selector buttons. Adjust the Contrast control to the one o'clock position
and the Brightness control to halfway between one and two o'clock. To
write in a color with the pen, select the desired color or combination of
colors and depress the Write button. Now hold the pen so that the small
white pen marker spot appears on the screen. Depress the Enable button
on the pen and it will write. If no pen marker spot can be seen the
Brightness control is set too low.
To erase a color with the pen repeat the above procedure but
depress the Erase Color button. The colors are selected by the color
selector buttons.
Writing or erasing an outline is accomplished in the same
manner as above except that the Draw Outline or Erase Outline button is
depressed and the color selector buttons have no effect.
To color, depress the Color button, point the pen to the
interior of the outline which is to be colored and depress the Enable
button. The color is chosen by the color selector buttons.
The entire outline or all of one color may be erased at any
time by depressing the Outline Erase button or the Color Erase button.
Colors to be erased are selected by means of the color selector buttons.
The Outline Erase and Color Erase buttons are independent of all other
buttons .
-106-
There are several adjustments that can be made to the Tricolor
Cartograph. There are numerous adjustments for the color monitor and the
video disc. These will not be discussed here. Instructions for these
adjustments may be found in the respective manuals for these units. Five
circuits in the Processor have adjustments. They are: the Pen Shaping
Circuit, the pen thresholding amplifier, the Video to Logic Converter,
the 3 -Input Video Adders and the Voltage Controlled Oscillator.
The thresholding amplifier should be set at a level which will
completely clip the noise pulses generated by the monitor flyback circuit,
This should be done after the system is thoroughly warmed up. (~ one
hour) .
After the threshold circuit has been adjusted the pen shaping
circuit should be adjusted so that no extraneous noise pulses appear on
the screen.
The Video to Logic Converter can be adjusted to respond only
to signals above a certain threshold level. Small adjustments in this
level are made with the potentiometer. Large adjustments require that
the bias diodes in the circuit be changed. The pen threshold may be
set at minimum but the outline threshold can only be as low as is
possible without picking up false outline pulses. Neither thresholds
must not be set so high that ligitimate pen or outline pulses are clipped.
The 3 -Input Video Adders have four gain adjustments, one for
each of the' 3 video inputs and one for their sum. The video from the
disc will be in the range 0.7 to 1.0 volts. The adders should be
adjusted so that each of the inputs (video, outline and pen), when used
along, produces a 1 volt signal at the output.
There are three adjustments to thi age Controlled Os cilia
The zero adjustment provides a means of setting the input t
to zero when the incoming AFC pulse is at the normal rate (l5,750Hzy and
width (9.5 (isec). The frequency adjustment capacitor provides a limited
range for adjusting the oscillator frequency to 8MHz. Large fre
adjustments must be made by changing the inductance. The gain adjustment
allows adjustment of the frequency shift for a given input pulse width
change.
■108-
BIBIIOGRAPHY
Barney, Walter. "New Terminals in Display Picture," Electronics .
January 8, 1968. McGraw Hill Book Co.
Bycer, Bernard B. Digital Magnetic Tape Recording: Principles and
Computer Applications . Hayden Book Co., Inc., New York, 1965.
Esch, J. W. , et al. Artrix Final Report , Report #238 Digital Computer
laboratory, University of Illinois, Urbana, Illinois,
June 20, 1967.
Glasford, Glenn M. Fundamentals of Television Engineering . McGraw
Hill Book Co. 1955.
Giles, James N. Fairchild Semiconductor linear Integrated Circuits
Applications Handbook . Fairchild Semiconductor, Mountain View,
California, I967.
Hendrickson, Herbert C. A High-Precision Display System for Command and
Control Information Display '. July /August, I967.
Howard, James N. , Ed. Electronic Information Display Systems . Spartan
Books, Washington, 1963-
Kiver, Milton S. Color Television Fundamentals . McGraw-Hill Book Co.
New York, 1964.
Kubitz, W. J. Quarterly Technical Progress Report , Digital Computer
laboratory, University of Illinois, Urbana, Illinois. October,
November, December, 1966. #COO-l469-0064.
Also: January, February, March, 1967 COO-II469-OO7I
July, August, September, 1967 COO-1469-0073
January, February, March, 1^68
Poole, Harvey H. Fundamentals of Display Systems . Spartan Books,
Washington, I966.
Richards, R. K. Electronic Digital System . John Wiley and Son, Inc.
New York, I966.
Risko, Frank D. "Design Factors in Magnetic Pulse Recording." Electro-
Technology , December, 1967-
Southworth, Glen R. "A Magnetic Disc Video-Scan Converter," a paper
presented at the 102nd Technical Conference of the SMPTE,
September 17-22, 1967.
VITA
William John Kubitz was born in Freeport, Illinc
27, 1938. He graduated from Freeport High School in 1957- In 196l he
received his B.S. in Engineering Physics from the University of Illinois.
He received his M.S. in Physics from Illinois in I962. From 1962 to
I96U he was a development engineer with the General Electric Company.
In I96U he returned to the University of Illinois to work toward a Ph.D.
in Electrical Engineering. He is a member of the IEEE.
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